World experience in the use of excess sewage sludge

Abstract

The world experience of neutralization and disposal of excess sludge of urban sewage is considered. The sludge generated during the technical treatment of municipal wastewater is dangerous, has low dehydration, the percentage of moisture is more than 96%, contains some pathogenic and organic substances, as well as heavy metals. In the Mangystau region of Aktau (Kazakhstan) at a sewage treatment plant, sewage sludge is mainly accumulated on silt sites after minimal treatment. The main directions of neutralization and disposal of excess sludge used in Asian and European countries are generalized. For example, while authors from China conducted research on ultrasonic chemical treatment of urban sludge and drying by artificial methods, authors from Europe paid more attention to the disposal of excess sludge from municipal wastewater, in the form of road surface additives, cement strength additives or modified bentonite for further use. Sewage sludge as a safe fertilizer in the national economy. Their advantages and disadvantages are shown, considering environmental and economic efficiency. The advantages of many studies can be indicated by the efficiency of the secondary use of sewage sludge, as well as a significant reduction in the area allocated for the storage of precipitation data. The disadvantages of these studies can indicate significant economic and time costs, which are ultimately compensated by the positive results of their secondary use.